Find out for yourself how the new fast Micro Four Thirds prime from Olympus shapes up

The new fast (f/1.8) medium telephoto prime lenses that Olympus now has on offer for Micro Four Thirds photographers are all about limiting depth of field when you need to. Both these lenses, the m.Zuiko 45mm f/1.8 and the new m.Zuiko 75mm f/1.8, are designed to be used wide open at f/1.8 with minimal sacrifice of sharpness and definition. The 45mm optic has already earned near-cult status.

In a typical portrait scenario, using the 45mm lens you might be 0.6m from the subject. At f/1.8 the depth of field would be just under half a centimetre in front of and behind the point of prime focus, so about 0.9cm in total.

Take the 75mm lens and compose an identical framing of the subject and you will be further back - at about a metre instead of 0.6m. The depth of field with this lens at f/1.8 will be, you may be surprised to discover, pretty much the same as the 45mm lens.

So what differentiates these two lenses? Obviously, the increased focal length means the 75mm has more reach. This supports Olympus' statement that the lens will be useful for indoor events, like concerts and sports events, where light can't always be relied upon to be bright. But I suspect that most users will be pointing this lens at heads and shoulders for portrait photography. In this situation the big differentiator is the isolation of the subject from the background. Although the 45mm lens offers the same depth of field as the 75mm if the subject field of view is the same, the backgrounds will look quiet different as our examples show below:

First, taken with the m.Zuiko 75mm f/1.8 @f/1.8

Secondly, taken with the M.Zuiko 45mm f/1.8 @f/1.8. The model is roughly the same size in the frame but the camera is closer than with the 75mm shot. The background covered is wider and so busier, even though it is blurred.

Here is a crop to the model's head from the 75mm shot.

Finally, 1:1 (100% or one image pixel to one screen pixel) from the 75mm shot.

Clearly, the 75mm lens beats the 45mm for sheer quality of background blur and bokeh, but the sharpness of in-focus areas at f/1.8 remains pretty much as good as the 45mm. You certainly don't need to stop either lens down in order to get tack-sharp images.

Samples gallery

To help illustrate the performance of the new 75mm f/1.8 and to compare it directly with the popular 45mm f/1.8, here is a gallery of 11 shots. You can view the full size, un-edited, JPEG in your browser or download it to your computer. Each shot has a download link to the corresponding RAW file. Please note that these images are copyrighted and provided for your personal evaluation only. Please don't re-post the actual images to other websites. If you wish to share these images with others, please post a link to this page.

Image 1: This scene was shot indoors with the m.Zuiko 75mm f/1.8 and lit with a mixture of fluorescent tubes and natural light that didn't add up to much brightness and yet at f/1.8 we're enjoying 1/250th second at ISO 200.
Shutter Speed: 1/250 sec
Aperture: f 1.8
ISO: 200
Focal Length: 75 mm
Link to RAW file

Image 2: Here is the same scene shot with the m.Zuiko 45mm f/1.8, also at f/1.8. The foreground is quite similar to the 75mm but you can see that the background has more definition and less blur with the 45mm lens.
Shutter Speed: 1/320 sec
Aperture: f 1.8
ISO: 200
Focal Length: 45 mm
Link to RAW file

Image 3: In bright direct light the highlights are unsurprisingly harsh, but there is just enough shutter speed to shoot at f/1.8 and ISO 200. You do, however, need to be carefully with the limited depth of field. The model on the right is mostly out of focus in this shot.
Shutter Speed: 1/3200 sec
Aperture: f 1.8
ISO: 200
Focal Length: 75 mm
Link to RAW file

Image 4: Reasonably close in with this portrait and still shooting at f/1.8 the 75mm lens really shows how effective it is at blurring the background.
Shutter Speed: 1/800 sec
Aperture: f 1.8
ISO: 200
Focal Length: 75 mm
Link to RAW file

Image 7: With the 45mm the background blur is pretty good, but there is more of the background visible and that makes the background more 'busy'.
Shutter Speed: 1/800 sec
Aperture: f 1.8
ISO: 200
Focal Length: 45 mm
Link to RAW file

Image 9: There is no sacrifice of subject details at f/1.8 in order to get the background blur you need to isolate the subject.
Shutter Speed: 1/500 sec
Aperture: f 1.8
ISO: 200
Focal Length: 75 mm
Link to RAW file